The present invention relates, in general, to semiconductor devices, and more particularly, to quantum well semiconductor devices.
In the past, the semiconductor industry has utilized a variety of methods for implementing quantum well semiconductor devices. One particular problem with prior quantum well devices such as lasers, is the operating lifetime or reliability. During the operational lifetime, the efficiency typically decreases at a rate of approximately two to three percent per thousand hours of operation.
To increase the lifetime, indium typically is added to the material used to form the quantum well. For example, to increase the reliability of an aluminum gallium arsenide/gallium arsenide (AlGaAs/GaAs) laser, indium is added to a portion of the GaAs compound thereby forming an indium gallium arsenide (InGaAs) alloy. Although the addition of indium increases the lifetime, it also decreases the band gap within the quantum well. The narrower band gap results in increasing the wavelength of light emitted. This increased wavelength is not easily detectable by conventional photodiodes, thus, more expensive detectors must be utilized. Consequently, using indium to increase the operating lifetime also increases the cost of a system utilizing such quantum well emission devices.
Accordingly, it is desirable to have a quantum well semiconductor device that has a high indium content in the material that forms the quantum well and that has a quantum well band gap that is substantially not affected by the indium.